Battery packs each of which includes a plurality of batteries housed in a case so as to output a predetermined voltage and have a predetermined capacity are widely used as power sources for various equipment, vehicles, etc. For these batteries packs, there is a newly employed technique of connecting general-purpose batteries in parallel or in series to form modules of battery assemblies each outputting a predetermined voltage and having a predetermined capacity and of variously combining such battery modules to comply with various applications. This module technique enables reduction in size and weight of battery modules by enhancing performance of batteries housed in the battery modules, and therefore, has advantages such as improved workability in packaging battery packs and high flexibility in installing the battery modules in limited space of vehicles or other equipment.
On the other hand, along with enhancement of the performance of batteries housed in battery packs, higher importance is placed on, in addition to the safety of each battery, the safety of the battery packs each of which includes a plurality of batteries. In particular, when a gas is produced by heat generated by, e.g., an internal short-circuit occurring in a battery and a safety valve operates to release the gas having high temperature to the outside of the battery, normally operating batteries located near the battery suffering the internal short-circuit are exposed to and affected by the gas having high temperature, thereby causing a risk of a chain of degradation in the batteries.
To address such a problem, Patent Document 1 describes a power supply device in which a case housing a plurality of batteries is partitioned by a partitioning wall into a battery chamber housing the batteries, and an exhaust chamber through which a high-temperature gas released from the battery is exhausted, wherein the power supply device includes an exhaust mechanism in which an opening of a safety valve of each battery is in communication with the exhaust chamber. With the exhaust mechanism thus configured, the high-temperature gas released due to occurrence of a failure through the safety valve of the battery is allowed to flow into the exhaust chamber without flowing into the battery chamber, and is exhausted outside the case via an exhaust port of the case. This can prevent adjacent normal batteries from being subjected to the high-temperature gas released from the battery suffering the failure, so that the influences on the normal batteries can be reduced.